The present invention relates to a starting system (a starter) for an internal combustion engine.
In a conventionally well known starting system for an internal combustion engine, a pinion is mounted on a rotary shaft (an output shaft) of a starting motor via a one-way clutch and a helical spline, a ring gear is fixed on a crankshaft, the pinion is located not yet to bring in mesh with the ring gear when an engine key switch (a starting switch) is turned OFF. The starter is designed so that when the engine key switch is turned ON, the pinion moves in an axial direction so as to be brought in mesh with the ring gear via a shift mechanism, further with an operation of a motor, rotational force of the motor is transmitted to the crankshaft via the pinion and the ring gear.
There are various modes for a mechanism for bringing them in mesh with each other between the pinion and the ring gear. For example, in a magnetic shift mode, the pinion is brought in mesh with the ring gear by utilizing attractive force of an electromagnet and by means of a torsion spring and a shift lever, a plunger is moved by means of electromagnetic attractive force so as to push out the pinion, when the pinion is not collided with the ring gear, both of them are smoothly brought in mesh with each other so as to close a contact for rotation of the motor (the starting motor) Further, when both of them are not yet brought in mesh with each other by colliding teeth of the pinion with that of the ring gear at end faces, a torsion spring is deflected so as to close the contact, an armature is rotated by carrying a current to the motor, then the pinion is rotated while being pushed to the ring gear by means of pressure of the torsion spring and thrust due to a helical spline on the rotary shaft of the motor, so that the pinion is brought in mesh with the ring gear by deviating the teeth of the pinion.
Other than that, as a mode to decrease to least possible impact force due to collision of the pinion with the ring gear, there is such a mode as that when the key switch is turned ON, the pinion is moved up to the end faces of the teeth of the ring gear via a shift mechanism, simultaneously, the motor is rotated with its fine speed by carrying a fine current to the motor via an attraction coil employed for the shift mechanism, with this rotation, the pinion is moved from a pressurizing state against the teeth of the ring gear so as to be brought in mesh with each other, and at the time of being brought in deep mesh with each other for both of them, the contact of a magnetic switch is closed so that the motor is to be rotated with full power.
Further, recently, as disclosed in Japanese Unexamined Patent Publication H9-53550, for example, such a mode is proposed as that, the ring gear is mounted on a rotary shaft (an input shaft) of a vehicular generator (an alternator) without mounting on the crankshaft, the engine switch is turned ON so as to move the pinion on a side of the ring gear via the helical spline, so that the pinion and the ring gear are brought in mesh with each other, thereafter, when the motor is rotated, its rotational force of the motor is transmitted with power to the crankshaft via a route from the pinion, the ring gear, the input shaft of the generator and a pulley, belt, and to the crankshaft.
In this conventional example, when the key switch is turned ON, the magnetic switch is turned ON so as to carry a current to the armature of the motor, thereby, the output shaft of the motor is rotated, so that the pinion and the ring gear are brought in mesh with each other by means of an advanced movement of the pinion due to the rotation of the output shaft of the motor and the thrust from the helical spline.
After completion of starting operation, the pinion is separated from the ring gear by mean of action of a return spring and the one-way clutch and action of the helical spline, when engine speed further increases, the rotation of the crankshaft is transmitted to the input shaft of the generator, and the input shaft can rotate with a sufficient revolutionary speed for a power generation operation.
As described above, in a case where the ring gear is mounted on the input shaft of the generator, since a power transmission mechanism ranging from the pinion to the crankshaft is constituted of two stage reduction gear mechanisms of the pinion and the ring gear, and of the belt and the pulleys, so that a reduction gear ratio between the ring gear and the pinion can be reduced by an amount of that degree, there is advantage for realizing a decrease in diameter of the ring gear.
In any of modes of the prior art described above, since collision force is occurred when the pinion and the ring gear are brought in mesh with each other, it is desired from the point of view for preventing the gears from wearing and damaging that the collision force is to be decreased to least possible degree.
Especially, in a recent vehicle, such a mode of operation is proposed as that other than exerting a starting operation by means of an engine key switch operation, when the vehicle becomes, for example, at its zero speed state, that is, a vehicle stoppage state due to a red light of a traffic signal or the like during driving of an internal combustion engine, a temporal fuel stoppage is carried out by means of an engine controller so as to stop the engine(Idling stop), when a driver depresses an accelerator, the engine controller determines that traveling is required and the engine is controlled for restarting. However, with the adoption this mode, the conventional starting system tends to increase in a frequency of collisions. Therefore, a reduction in above-described collision force is furthermore demanded.
An object of the present invention is, firstly, to provide a starting system of an internal combustion engine capable of remarkably improving durability and service life of the ring gear and the pinion by eliminating collision of the pinion with the ring gear caused by bringing in conventional mesh with each other between the pinion and the ring gear.
Another object of the present invention is to provide a starting system of an internal combustion engine capable of realizing a decrease in diameter of a ring gear, miniaturization of the system, and in turn, a reduction in load of an internal combustion engine.
(1) A first aspect of the invention is characterized in that in a starting system for an internal combustion engine including a pinion mounted on a rotary shaft of a starting motor and a ring gear for transmitting rotational force of the motor to a crankshaft of the internal combustion engine by bringing the ring gear in mesh with the pinion, a rotatable shaft (hereinafter, this shaft is called xe2x80x9can intermediate shaftxe2x80x9d) is interposed between an output shaft of the motor and the crankshaft, the ring gear is mounted on this intermediate shaft via a bearing, this ring gear is normally brought in mesh with the pinion directly or indirectly via a rotation transmission member, one clutch element for coupling and releasing of the coupling both the intermediate shaft and the ring gear is fitted by a spline to the intermediate shaft, the other clutch element is provided on the ring gear, and the one clutch element fitted by the spline is set so as to move on a side of the ring gear via a shift mechanism when a starting switch of the internal combustion engine is turned ON and so as to be separated from the ring gear when the starting switch is turned OFF, and the intermediate shaft is coupled with the crankshaft via a power transmission mechanism to constitute a reduction gear mechanism when viewed from a side of the intermediate shaft toward a side of the crankshaft.
According to a structure described above, the pinion and the ring gear are normally in a state for bringing them in mesh with each other, however, since a clutch element (hereinafter it is called xe2x80x9ca movable clutchxe2x80x9d) fitted by the spline to the intermediate shaft is not in a joining state with a clutch element (hereinafter it is called xe2x80x9ca stationary clutchxe2x80x9d) on the side the ring gear except at the time of starting the internal combustion engine, the ring gear is in a freely rotatable state on the intermediate shaft via the bearing.
When the starting switch of the internal combustion engine is turned ON, the movable clutch element is joined with the stationary clutch on the side of the ring gear by shifting on the intermediate shaft, further, since the movable clutch element is fitted by the spline, when the starting motor is rotated, its rotational force is transmitted to the crankshaft via the pinion, the ring gear, the clutch elements (the stationary clutch element and the movable clutch element), the intermediate shaft, the power transmission mechanism, and the crankshaft, and the internal combustion engine starts operation.
After completion of the starting operation, when the starting switch is turned OFF, the movable clutch element is separated from the ring gear, and a clutch joining is released.
When this clutch joining is released, since the ring gear is in the state to be freely rotatable on the intermediate shaft via the bearing as described above, power of the crankshaft during driving of the internal combustion engine is transmitted up to the intermediate shaft, and is not transmitted to the side of the ring gear. Accordingly, there is no trouble, even if the ring gear and the pinion on a side of the starting motor are normally in a state for bringing them in mesh with each other.
According to the present invention, since the ring gear and the pinion of the starting motor are normally in the state for bringing them in mesh with each other, there occurs no collision between the ring gear and the pinion even at the time of starting, so as to prevent both the gears (the ring gear and the pinion) from wearing and damaging. Further, since the intermediate shaft and the crankshaft are coupled with each other via a power transmission mechanism to constitute the reduction gear mechanism viewed from the side of the intermediate shaft toward the side of the crankshaft, a reduction gear ratio between the pinion and the ring gear to constitute its upper stage reduction gear mechanism is possible to be lessened, a decrease in diameter of the ring gear can be realized.
As the intermediate shaft described above, for example, accessories such as a rotary shaft of a vehicular generator (an input shaft of a generator) or a rotary shaft of a vehicular compressor is conceived, during driving after completion of the starting operation of an internal combustion engine, power from the crankshaft is transmitted to this intermediate shaft via the power transmission mechanism, power generation operation or compressor operation according to requirement is to be conducted. In this case, the power transmission mechanism constitutes a step-up gear mechanism when viewed from a side of the crankshaft toward a side of the intermediate shaft, revolutionary speed necessary for the generator and the compressor can be secured. Further, when performing the power generation operation or the compressor operation, the intermediate shaft (the input shaft of the generator or the input shaft of the compressor) is capable of rotating with little regard to the ring gear, therefore a decrease in load of the generator or the compressor can be realized.
(2) A second aspect of the invention is characterized in that in a starting system for an internal combustion engine including a pinion mounted on a rotary shaft of a starting motor and a ring gear for transmitting rotational force of the motor to a crankshaft of the internal combustion engine by being brought in mesh with the pinion, the ring gear is mounted on the crankshaft via a bearing, this ring gear is normally brought in mesh with the pinion directly or indirectly via a rotation transmission member, further, one clutch element for coupling and releasing of the coupling both the crankshaft and the ring gear with each other is fitted by a spline to the crankshaft, the other clutch element is provided on the ring gear, and the one clutch element fitted by the spline is set so as to move on a side of the ring gear via a shift mechanism when a starting switch of the internal combustion engine is turned ON and so as to be separated from the ring gear when starting switch is turned OFF.
In the present invention, an intermediate shaft which is employed in the case of the first aspect of the invention, is eliminated and the ring gear is directly mounted on the crankshaft via the bearing, a state normally for bringing them in mesh with each other between the ring gear and the pinion is maintained.
Both the pinion and the ring gear are in the state normally for bringing them in mesh with each other, except at the time of starting of the internal combustion engine, a clutch element (hereinafter, it is called xe2x80x9ca movable clutch elementxe2x80x9d) fitted by the spline to the crankshaft is not in a joining relationship with a clutch element (hereinafter, it is called xe2x80x9ca stationary clutch elementxe2x80x9d) on the side of the ring gear, therefore, the ring gear is in a state to be freely rotatable on the crankshaft via the bearing.
When the starting switch of the internal combustion engine is turned ON, the movable clutch is shifted on the intermediate shaft, so as to be joined with the stationary clutch element on the side of the ring gear, further, since the movable clutch element is fitted by the spline to the crankshaft, when the starting motor is rotated, its rotational force is transmitted to the crankshaft via the pinion, the ring gear, the clutch elements (the stationary clutch element and the movable clutch element), and the crankshaft, so that an operation of the internal combustion engine is started.
When the starting switch is turned OFF after completion of the starting operation, the movable clutch element is separated from the ring gear so as to release the clutch joining.
In the present invention, since the ring gear and the pinion of the starting motor are normally in the state for bringing them in mesh with each other, even at the time of starting, never is occurred such as a collision between the ring gear and the pinion so as to prevent both of the gears (the pinion and the ring gear) from wearing and damaging.